Handlebar riser



FIG. 1 is a perspective view of a handlebar riser according to my design engaged with a motorcycle handlebar;

FIG. 2 is a bottom view of a handlebar riser according to my design;

FIG. 3 is a top view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is an opposite side view thereof; and,

FIG. 7 is a rear view thereof.

The portions shown in broken lines form no part of the claimed design. 

The ornamental design for a handlebar riser, as shown and described. 